REPORT ON THE SCHIZOPODA. 



11 



Legs generally uniform in structure, not adapted for walking, geniculate and densely 

 setose, without any distinct dactylus ; posterior pairs more or less imperfectly developed. 

 Brancliise (podobrancluje) wholly uncovered, digitiform-arboresccnt, the posterior pairs 

 rather complex, sending ofi" a branch beneath the trunk. Egg-pouch, when present, 

 placed beneath posterior part of trunk, single or double, not formed by any incubatory 

 lamellae. Caudal limbs strongly developed in both sexes, natatory, inner plate provided 

 with a secondary lobe, and in the male modified on the first two pairs as copulative 

 organs. Luminous globules of complicated structure generally present on both the 

 anterior and posterior divisions of the body. Propagation by means of spermatophores. 

 Development very complex, the free larva passing through the Nauplius and Zoea-stages. 



Genera. 



1. Eiiphaima, Dana. 



2. Thysanopoda, M.-Edw. 



3. Bentheuphausia, n. gen. 



4. Nyctiphanes, G. 0. Sars. 



5. Boreophausia, n. gen. 



6. Thijsanoeisa, Brandt. 



7. Nematoscelis, G. 0. Sars. 



8. Stylochdron, G. 0. Sars. 



4. Mysid^. 



Carapace generally rather small ; its posterior part only loosely covering the trunk, 

 the segments of which are distinctly defined, although very narrow and crowded together 

 in the dorsal part. Maxillipeds strong, with the exopodite well developed, natatoiy, 

 epipodite lanceolate and projecting within the branchial cavity. First pair of legs 

 modified as gnathopoda, the remaining legs uniform and generally of rather feeble 

 structure, the terminal part being in most cases subdivided into short setiferous articula- 

 tions, the dactylus, as a rule, small or wanting. No true branchiae present. Marsupium 

 in most of the genera composed of only two or three pairs of incubatory lamellae, issuing 

 from the bases of the hindmost pair of legs. Caudal limbs in female quite rudimentary, 

 not adapted for swimming ; in male either natatory or some of them modified to serve as 

 copulative organs. Inner plate of uropoda generally containing within its base a 

 peculiarly developed auditory apparatus. Development without any free metamorphosis. 



Geiiera. 



1. Petalopkthahmis, Suhm. 



2. Boreomijsis, G. O. Sars. 



3. Amhhjops, G. O. Sars. 



4. Fseudo77inia, G. 0. Sars. 



5. Erythrops, G. 0. Sars. 



6. Parerythfops, G. 0. Sars. 



7. Anchialus, Krdyer. 



8. Mysidopsis, G. 0. Sars. 



9. Leptoinysis, G. 0. Sars. 



10. Siriella, Dana. 



11. Mysideis, G. 0. Sars. 



12. Promysis, Dana. 



13. Euchcetomera, G. 0. Sars. 



14. Hemimijsis, G. 0. Sars. 



15. Mysis, Thompson. 



16. Macropsis, G. 0. Sal's. 



17. Mysidella, G. 0. Sars. 



18. Heteromysis, Smith. 



